Why Can’t I Smell?

What you’ll learn

Listen to the audio version below.

Audio Transcript:

Dr. Reddy:
Hey guys, welcome back to another episode of We Nose Noses. I’m Dr. Reddy and I’m joined here with Dr. Smith. Hi guys. And so today we’ll be discussing our sense of smell and what are potential reasons for why one might not be able to smell well. I’ll let Dr. Smith get started.

Dr. Smith:
Sure. So as usual, I always harp on this, but like a history is always helpful when we have patients come in and they have difficulty smelling. And one thing we wanna know is that like anosmia, which means I can’t smell anything, is it hyposmia, which is I have like partial anosmia. I can smell some things, but maybe not as strong as I used to smell those things. There’s also phantosmia, which is I’m smelling things that aren’t in the room. Nobody else is smelling these things. And like dysosmia, which is a, I’m having, these smells that used to smell one way, but now they’re smelling a different way. And so those are common kind of things that patients will complain of with smell disturbances. And I think to better understand some of these smell disturbances, I’ll just go over a little bit of how we smell, and then we can kind of go over the two of us, like why are some common causes of why we can’t smell and what things might be kind of done during a workup and evaluation for patients who come in with any of these smell disturbances.

So as we smell, odorant particles or little in the air come into the nasal cavity and go up to the upper part of the nasal cavity where we have a very specific sensory system aimed at smelling. And these little odorant molecules get into the lining of the nose and then they bind to essentially a nerve ending up at the top of the nasal cavity. they kind of go, these odorant particles go through the lining and then attach to the ending of the nerve. And the nerve ending are like these little hair fibers, these little cilia that come into the nasal passageway. And then those then send an impulse or a nerve up to a, into a nerve up to what’s called the olfactory bulb. And that olfactory bulb sits between the nose and the brain. And that’s kind of like our main smell center responsible for almost everything that we smell. And that smell is also often involved in things like taste. And so a lot of patients don’t realize that a lot of taste actually comes from smell. So it’s not uncommon that patients may also complain of like taste disturbances or things being off a little bit. I’ll kick it over to Dr. Reddy and he can talk a little bit about some of those things that may cause those things or the different areas that may have problems that we might need to work up and evaluate when someone comes in with these complaints.

Dr. Reddy:
Sure. So what I’ll what we’re kind of focusing on with ear, nose, and throat is either anosmia or hyposmia, which is either a lack of sense of smell or a reduction in the sense of smell. And the two broad categories for why this might happen is either the odor molecule is not able to get up to your smell center because of some obstruction or the smell center itself is not functioning properly, right? And let’s go over the former first, which is the smell center is not functioning properly. The most common causes of that is either previous viral exposure, like an upper respiratory tract infection and a virus actually from something as simple as a common cold to most recently COVID and other viruses can actually disrupt the smell center and permanently potentially alter it and or The other most common cause is trauma right from some type of the most common being is car accidents Where you get the whiplash injuries and the smell center neurons actually get damaged. So that’s the Issue with the smell center and the other common issue that we deal with is obstruction of odor molecules actually getting to the smell center. Maybe you can elaborate on that.

Dr. Smith:
Sure. So we see a lot of patients with sinus nasal inflammation. And so those can be patients with chronic rhinitis or chronic sinusitis or so inflammation in the nose and the sinuses. These patients can often get polyps within the nasal cavity as well. And those polyps can cause a physical obstruction.The rhinitis and the sinusitis can cause thickening of the lining inside the nasal cavity, which then is a blockage for that molecule to kind of diffuse through to the nerve. So those areas in the nasal cavity can get inflamed or obstructed. Sometimes even just a deviated septum or turbinates being enlarged, which are the heater humidifier system in the nasal cavity can cause some obstruction of air getting up there. So there’s a lot of physical obstructions that can be up there that we can see on exam that can give us clues as to why maybe someone has some difficulty.

Dr. Reddy:
And the other categories you mentioned with phantasmias and dysosmias, those can get quite complicated. There’s many potential causes to that. Things like medication side effects. There’s psychiatric illnesses that can sometimes cause this. There’s even if you have blocked sinuses, for example, sometimes you can smell the pus in your own face and nose and that might be what you’re smelling as well. Sometimes, you know, these certain neurocognitive disorders like Parkinson’s and Alzheimer’s can cause disturbances in your sense of smell and can change your sense of smell as well.

Dr. Smith:
So, yeah, a lot of studies show that an early sign of those disease processes or potentially a lack of smell or anosmia that can be a hint. So it certainly is something that we want to get worked up and evaluated. And it might be the ENT, it might be the primary doctor, maybe a little bit of both. And sometimes even a neurologist may need to get involved. Dr. Reddy, can you talk a little bit about what a normal evaluation may be consist of in an ENT office? And maybe if there’s any studies or any procedures that might be done to kind of assist with diagnosing maybe what the underlying culprit might be.

Dr. Reddy:
Sure. So there is a test that can be done that actually quantifies your sense of smell rather than just going over how you’re feeling about it. Right, and so one of the most commonly used tests is called the Upsit test. And that can help give us a numerical value of how severe your potential smell disturbance is.

Dr. Smith:
In general, what would you tell somebody an upsit test is?

Dr. Reddy:
It’s basically a scratch and sniff test.

Dr. Smith
Yeah, exactly. Yeah.

Dr. Reddy:
Yeah. So it’s more helpful for research purposes. It’s not terribly helpful in the office, but it’s something we can do. Yeah.

Dr. Smith:
Sometimes I can get patients peace of mind too. They see that their score got better and things are improving.

Dr. Reddy:
And the most common test with it, what you do is a nasal endoscopy. We put a little camera in your nose and we take a look in the nooks and crannies of your nose. And we’re mainly evaluating for any type of obstruction that’s leading, that’s causing the odor molecules not to be able to get up to your smell center. And then there’s all sorts of other tests too that we can present to you order. Do you want to elaborate on that?

Dr. Smith:
Yeah, sure. Like if you can’t find an actual culprit, like if we look in there and there’s not pus draining or polyps or some major inflammatory thing going on, maybe someone’s already kind of failed some normal nasal treatments like nasal steroids and antihistamines, sinus washes, et cetera. Sometimes we’ll do some imaging as well to make sure that there’s not actually a tumor or a stroke associated with this loss of smell. So we’re looking for any tumor along that olfactory bulb or the center going to the brain that might be causing that. Sometimes meningiomas and other tumors along the brain covering can cause these.

Sometimes there are nerve tumors that can cause these. So they’re not always aggressive or malignant tumors, but sometimes even benign brain tumors can cause these things too. So there’s not a clear cut reason for it. It’s been lasting for more than an adorable period of time. Then often we’ll take a look with some imaging studies as well to make sure that there’s nothing else going on. Anything else that you typically do in the workup and talking to a patient about this?

Dr. Reddy:
I mean, I think we touched on some of the major things and we’ll go over treatment options and a future episode. But one pearl that I’ve noticed a lot, at least in our patient population, is that a lot of patients don’t always complain as much about the smell than they do complain about the taste problems.

Dr. Smith
I would agree.

Dr. Reddy:
And to be precise with the terminology, taste itself is not specifically altered by the lack of smell. It’s really the flavor of food that’s affected. So flavor is your perception of what food tastes like. And it’s really a combination of taste plus smell, right? And sometimes even sight. And sight and consistency.

Dr. Smith
For sure.

Dr. Reddy:
A lot of flavor of food comes from what we call retro-olfaction. So it’s not necessarily that you’re just smelling the food directly prior to eating it. It’s actually that you’re chewing the food and then while you’re chewing it, the odor molecules get released in the back of your throat, which then travels up behind your nose and up into your smell center. And that’s typically what gets disrupted significantly when you have a lack of sense of smell. And so a lot of our patients, just complain of bland tasting food. They can’t tell different foods apart. And that’s some of, happens to be some of their biggest complaints.

Dr. Smith:
Excellent. Good point.

Dr. Reddy:
Yeah. but I think that’s all we have for today. Right?

Dr. Smith
Yeah, we wanted to keep it short and sweet. So hopefully you guys have enjoyed, this podcast and as always make sure you like and subscribe.

Dr. Reddy:
Take care.

In cases where nasal polyps or chronic sinusitis severely affect the sense of smell, sinus surgery can remove the obstructions and potentially restore a patient’s olfaction.